In current communications systems, control information of data is transmitted by a physical downlink control channel (PDCCH) or an enhanced physical downlink control channel (E-PDCCH). The control information includes information such as resource allocation, a modulation format, and an encoding format that facilitates data scheduling, and 16 cyclic redundancy check (CRC) bits. Therefore, there are usually tens of information bits in the control information in total. However, the PDCCH is only allowed to occupy the first three symbols of a subframe. Therefore, the current PDCCH can accommodate only a limited quantity of control information.
As terminals increase and various data services appear, data traffic is to increase abruptly. Therefore, a future communications system or a fifth-generation mobile communications system needs to be capable of supporting connection of massive devices and reception/transmission of large amounts of data, and a large quantity of control information is required to control the reception/transmission of data. However, current control channels can accommodate only a limited quantity of control information, and consequently cannot satisfy the reception/transmission of large quantities of control information caused by connection of large quantities of devices and reception/transmission of large amounts of data.